It's the height of the spring real estate season in Phoenix, Arizona. If you're trying to buy a house in that city, well, Godspeed to you.

Just a few years ago, the area was pummeled by the mortgage crisis. But now realtors and buyers are frustrated with how fast the market is recovering. The median sales price is up nearly 40 percent from the same time last year.

For an idea of how strange things have gotten, consider the story of Realtor Brad Bohn. He's about to close a deal on a five-bedroom house for his clients in the suburb of Tempe. He won't describe the deal because a competitor might catch of wind this story.

"Somebody could pull up right now. Walk in. Like it. Go back to the office with their realtor. Write up a cash offer and I'm probably out of luck," says Bohn, standing a few feet from the house.

Bohn's clients have been looking for a house this good for a year. The area's housing stock is in short supply, bidding wars are driving up prices, and buyers are worried about getting priced out of the market.

"If they like it, it's not 'think about it 24 hours,'" Bohn says. "It's write an offer right now. Think about it later during the inspection period."

But wait, haven't we been through this before?

"I can think of eight reasons why it's not a bubble," says Michael Orr, a researcher with Arizona State University's W.P. Carey School of Business. First, unlike 2005, people are actually living in the homes they're buying, Orr says. Second, there aren't enough construction workers to build new houses, so oversupply won't be a problem for a while. And third:

"In the last bubble we had the availability of loans to almost anyone who could breathe," Orr says.

So, yeah, finding a house to buy is tough. But Orr says it's not time to go on bubble watch just yet.

1. The population is growing much faster than the housing stock in Greater Phoenix.

2. Prices are being driven up by a chronic lack of supply, not by excess demand.

3. Prices are still at the same level as 9 years ago. They still have a lot of room to increase yet.

4. Most buyers are putting their own money in with cash or large deposits, not borrowing it all from foolish lenders.

5. Lenders are still being ultra cautious.

6. Investors are mostly buying to rent - if and when they sell it is a neutral event for the market - one extra home becomes available and one extra family needs a home to live in.

7. There are major long term obstacles to developer trying to increase the supply of new homes.

8. Phoenix has a low vacancy rate both in homes for rent and for sale. Multiple generations and even multiple families are sharing single homes.

9. No bubble has ever occurred in the same market twice in the same generation. However after a recent bubble everyone is hyper-sensitive to every price increase and numerous false cries of "bubble" are par for the course.